3.1.6 ATP - A Level Biology

AQA A-Level Biology

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3.1.6 ATP

SPECIFICATION A single molecule of adenosine triphosphate (ATP) is a nucleotide

derivative and is formed from a molecule of ribose, a molecule of adenine and three phosphate groups.

Hydrolysis of ATP to adenosine diphosphate (ADP) and an inorganic phosphate group (Pi) is catalysed by the enzyme ATP hydrolase. The hydrolysis of ATP can be coupled to energy-requiring reactions within cells. The inorganic phosphate released during the hydrolysis of ATP can be used to phosphorylate other compounds, often making them more reactive.

ATP is resynthesised by the condensation of ADP and Pi. This reaction is catalysed by the enzyme ATP synthase during photosynthesis, or during respiration.

Source: AQA Spec

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3.1.6 ATP

ATP

ATP is a very important molecule in all living things and without it we wouldn't be able to function.

ATP is the immediate source of energy in a cell

Plant and animal cells release energy from glucose in a process called respiration Cells cannot get this energy directly from glucose so, in respiration, the energy

released from glucose is used to make adenosine triphosphate (ATP) ATP is made from the nucleotide base adenine combined with a ribose sugar and

three phosphate groups It is known as a nucleotide derivative because it is a modified form of a

nucleotide When it is made, ATP diffuses to the part of the cell that requires the energy The energy is stored in high energy bonds between the phosphate groups and is

released via hydrolysis reactions

The structure of ATP shows the basic components of a two-ring adenine, five-carbon ribose, and three phosphate groups.

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3.1.6 ATP

How ATP Carries Energy

ATP is described as energy intermediate or an immediate energy source because it released energy rapidly in a single step hydrolysis.

When energy is needed by the cell, ATP is broken down to ADP (adenosine diphosphate) and P (inorganic phosphate)

In the hydrolysis reaction, a phosphate bond is broken and energy released to be catalysed by the enzyme ATP hydrolase

ATP hydrolysis can be coupled to other reactions in the cell - the energy can be used directly to make the coupled reaction happen (instead of being lost as heat)

Released organic phosphate can be added to another compound (this is called phosphorylation) which often makes the compound more reactive

ATP can then be re-synthesised in a condensation reaction between ADP and P. The enzyme ATP synthase catalyses it during both respiration and photosynthesis.

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How Cells Use ATP Energy to Power Cellular Work

3.1.6 ATP

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